The invention pertains to a method for manufacturing a brake disk with of a carrier part and a friction ring, as well as to a core moulding tool that is used during the course of the manufacture of such a brake disk. In brake disks of the discussed type, on the one hand the carrier part serves for mounting the friction ring. On the other hand the wheel hub of a vehicle wheel is also mounted on the carrier part. For this purpose the carrier part can be realized in a pot-shaped fashion such that the hub of the wheel can be directly mounted on its end face and the brake disk can be pushed onto a bearing on the motor vehicle axle. However, the carrier part may itself also form the hub, in which the respective wheel bearing is arranged. In this case, the wheel of the motor vehicle is usually connected to the carrier part by means of an intermediate flange.
Brake disks are subjected to high mechanical and thermal stresses in practical applications. This applies, in particular, to instances in which heavy utility vehicles need to be decelerated from high speeds. In this case, the predominant portion of the initial kinetic vehicle energy is converted into heat that is dissipated via the brake disk. An excessive heating of the friction ring may lead to stress cracks, in particular, in utility vehicles.
In order to counteract the risk of the formation of stress cracks as a result of overheating, the use of brake disk having only one positive connection between the carrier part and the friction ring has been proposed. Due to this measure, the disk is essentially able to expand radially in an essentially unobstructed fashion when heated. The formation of stress cracks can be effectively prevented in this fashion. In addition, the heat transfer from the friction ring to the carrier part and consequently to the wheel bearing is impaired such that their thermal stress is also reduced. However, the manufacture of such brake disks is problematic.
A method for manufacturing a brake disk with a cast friction ring and a cast pot is known from DE 199 31 140 A1. In this known method, the pot is cast into a previously cast friction ring, in the inner circumferential surfaces of which pocket-like recesses are arranged. The material of the pot penetrates into and fills out these pockets such that a reliable positive connection between the pot and the friction ring is ensured. Another example for casting a pot into a prefabricated friction ring is described in EP 0 933 551 A1.
Another possibility method for manufacturing brake disks with a carrier part and a friction ring that are positively connected to one another by means of a casting process is known from DE 39 20 418 A1. According to this known method, a carrier part is initially manufactured which comprises a collar-like peripheral web on one of its ends. Depressions are formed in the circumferential surfaces of the web, wherein the casting material of the friction ring penetrates into said depressions during its subsequent casting. A reliable positive connection between the friction ring and the carrier element of the brake disk can also be produced in this fashion.
In all previously discussed methods for manufacturing brake disks with a carrier part and a friction ring that are cast in separate production steps, the material of the respective element being cast on flows into recesses of the other element. Although this makes it possible to easily and reliably produce the positive connection between the friction ring and the carrier part, it is difficult to optimize the shape of the projections necessary for the positive connection with respect to their requirements.